### What this PR does / why we need it?
This PR sets the default format of GMM w2_weight in w8a8_dynamic to be
NZ to improve performance.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
- vLLM version: main
- vLLM main:
e40827280b
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Signed-off-by: Angazenn <supperccell@163.com>